Effect of Bunium persicum essential oil, NaCl, Bile Salts, and their combinations on the viability of Lactobacillus acidophilus in probiotic yogurt

The probiotic yogurt, with additional essential oil researches, has increased recently. Bunium persicum Boiss is a critical medicinal wild growing plant in Iran dry areas. In this study, Lactobacillus acidophilus was exposed to stress with B. persicum essential oil (BEO), NaCl, bile salts, and their combinations by 50 minimum inhibitory concentration (MIC) and then inoculated to the yogurt samples, which were stored at 4°C for 28 days. Indepen-dent parameters in this article are BEO 500 and 1000 ppm that the physicochemical, sensory properties, and L. acidophilus of viability in yogurt samples were assessed within the time. A steady increase in syneresis percent-age and acidity was observed, while pH values were reduced in all samples. The L. acidophilus survival decreased during storage time in all treatments. In addition, sensory scores showed a reduction trend in the samples. The survival rate of probiotic bacteria is also impacted by redox potential. Increasing the oxidation and resuscitation potential and increasing the hydrogen peroxide concentration due to the bacteria metabolic activity are among the factors that reduce the probiotic bacteria population in yogurt during storage. The most viability of L. acidophilus under stress with BEO compared with other stress treatments may be due to slight changes in pH during this period than in the stress treatments. Generally, it can be argued that the usage of BEO, NaCl, and bile salts at a MIC of 50% in yogurt stored in the refrigerator for 21 days provided a suitable environment for the storage and transmission of L. acidophilus, as recommended to the consumer and, therefore, the current results confirmed that the addition of probiotic and these materials improved the physicochemical and sensory characteristics of yogurt.